Ok, I've been thinking of my own moveset for the Hero of the Wild:
(By the way, some spoilers up ahead)
Tilts:
Link would use various weapons for his tilts, his jab would use a sword, and have him take out a sheild, which can block projectiles like the regular link. For his forward and down tilts, he should use a spear or halberd, his up tilt would be his sword again.
Smash Attacks:
Link would use axes here, or he could switch out like Peach does and use the different charge attacks for each weapon type.
Neutral B:
His Bow, obviously. Could possibly slow him down midair like in the game?
Side B:
He could use the bomb rune to create a bomb, but he will hold it above his head like he does in game, leaving him open, also he can input side B again to detonate it
(This is where it gets a bit spoilery)
Down B:
His down B should be Flurry Rush, this will act as Shulk's down B but you have to press the button multiple times for more damage
Up B:
This one should be Ravali's gale, he would fly up and deploy his paraglider as he falls down, think Megaman's custom move mixed with Peach's umbrella
Aerials:
Some combination of the three weapon types , I'm not completely sure, but his down air would be him using his jumping axe attack that would quickly send him downwards
Final Smash:
Here he should use the four divine beasts as an attack like in the true run against the final boss, this will do lots of damage, maybe it would be a cutscene like Shulk's or something, Link would hold his blade to the side like he does against the final boss and light would appear, anyone in the light is attacked by the four divine beasts.
Other Notes:
His sheild would be Daruk's protection, and only the visual style would change.
He could at least stick to walls, maybe climb them but only up a little or something.
His alts could be references to Zelda, or just his other clothes from the game (probably his swimsuit skin similar to Shulk)
His grabs wouldn't have a tether, so he would just use normal grabs and throws
His weapons would be on a break system, simular to Robin's
Technically you could have his custom moves use his sheika slate more, he has so many possibilities that it would be hard to put them all into one moveset